In packaging machines that produce sealed cartons containing food products or liquids, the carton blanks are typically introduced to the machine from a magazine. The magazine usually holds a stack of carton blanks in an unerected and compressed state, and urges the carton blanks toward a gate. The gate positions and holds the carton blanks so they can be picked one at a time by a mechanism that unfolds and erects the blanks to form cartons having side walls and unsealed top and bottom panels. After the bottom panel of the erected carton blank is sealed, a food product or a liquid can be received in the carton, the top panel of the carton can then be formed and sealed, and the filled and sealed carton can be dispensed from the packaging machine for eventual shipment to the consumer.
Many of today's carton blank magazines require the application of high pressure by the magazine's pusher mechanism to overcome the friction of the stack of carton blanks against the interior surfaces of the magazine, and to urge the stack of blanks toward the gate. Under such high pressure, blanks can become compressed to the extent that the blanks can become difficult to separate when they reach the gate. In such instances, two or more carton blanks can be improperly fed simultaneously to the packaging machine, thereby creating the potential for misalignment of the carton blanks in subsequent portions of the packaging machine and fouling of the packaging machine. When carton blanks are misaligned, food product can be wasted if the misalignment persists through the filling area. If the machine becomes fouled, then valuable production time can be lost during the time required to service the machine.